aboutsummaryrefslogtreecommitdiffstats
path: root/gcc-4.6/gcc/ada/s-finimp.ads
blob: 944fe6f114cbdbb4aa829c332753a83aec80a9a6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--    S Y S T E M . F I N A L I Z A T I O N _ I M P L E M E N T A T I O N   --
--                                                                          --
--                                 S p e c                                  --
--                                                                          --
--          Copyright (C) 1992-2009, Free Software Foundation, Inc.         --
--                                                                          --
-- GNAT is free software;  you can  redistribute it  and/or modify it under --
-- terms of the  GNU General Public License as published  by the Free Soft- --
-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
--                                                                          --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception,   --
-- version 3.1, as published by the Free Software Foundation.               --
--                                                                          --
-- You should have received a copy of the GNU General Public License and    --
-- a copy of the GCC Runtime Library Exception along with this program;     --
-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
-- <http://www.gnu.org/licenses/>.                                          --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

with Ada.Unchecked_Conversion;

with System.Storage_Elements;
with System.Finalization_Root;

package System.Finalization_Implementation is
   pragma Elaborate_Body;

   package SSE renames System.Storage_Elements;
   package SFR renames System.Finalization_Root;

   ------------------------------------------------
   -- Finalization Management Abstract Interface --
   ------------------------------------------------

   function To_Finalizable_Ptr is new Ada.Unchecked_Conversion
     (Source => System.Address, Target => SFR.Finalizable_Ptr);

   Collection_Finalization_Started : constant SFR.Finalizable_Ptr :=
                                       To_Finalizable_Ptr (SSE.To_Address (1));
   --  This is used to implement the rule in RM 4.8(10.2/2) that requires an
   --  allocator to raise Program_Error if the collection finalization has
   --  already started. See also Ada.Finalization.List_Controller. Finalize on
   --  List_Controller first sets the list to Collection_Finalization_Started,
   --  to indicate that finalization has started. An allocator will call
   --  Attach_To_Final_List, which checks for the special value and raises
   --  Program_Error if appropriate. The Collection_Finalization_Started value
   --  must be different from 'Access of any finalizable object, and different
   --  from null. See AI-280.

   Global_Final_List : SFR.Finalizable_Ptr;
   --  This list stores the controlled objects defined in library-level
   --  packages. They will be finalized after the main program completion.

   procedure Finalize_Global_List;
   --  The procedure to be called in order to finalize the global list

   procedure Attach_To_Final_List
     (L       : in out SFR.Finalizable_Ptr;
      Obj     : in out SFR.Finalizable;
      Nb_Link : Short_Short_Integer);
   --  Attach finalizable object Obj to the linked list L. Nb_Link controls the
   --  number of link of the linked_list, and is one of: 0 for no attachment, 1
   --  for simple linked lists or 2 for doubly linked lists or even 3 for a
   --  simple attachment of a whole array of elements. Attachment to a simply
   --  linked list is not protected against concurrent access and should only
   --  be used in contexts where it doesn't matter, such as for objects
   --  allocated on the stack. In the case of an attachment on a doubly linked
   --  list, L must not be null and Obj will be inserted AFTER the first
   --  element and the attachment is protected against concurrent call.
   --  Typically used to attach to a dynamically allocated object to a
   --  List_Controller (whose first element is always a dummy element)

   type Finalizable_Ptr_Ptr is access all SFR.Finalizable_Ptr;
   --  A pointer to a finalization list. This is used as the type of the extra
   --  implicit formal which are passed to build-in-place functions that return
   --  controlled types (see Sem_Ch6). That extra formal is then passed on to
   --  Move_Final_List (below).

   procedure Move_Final_List
     (From : in out SFR.Finalizable_Ptr;
      To   : Finalizable_Ptr_Ptr);
   --  Move all objects on From list to To list. This is used to implement
   --  build-in-place function returns. The return object is initially placed
   --  on a finalization list local to the return statement, in case the
   --  return statement is left prematurely (due to raising an exception,
   --  being aborted, or a goto or exit statement). Once the return statement
   --  has completed successfully, Move_Final_List is called to move the
   --  return object to the caller's finalization list.

   procedure Finalize_List (L : SFR.Finalizable_Ptr);
   --  Call Finalize on each element of the list L

   procedure Finalize_One (Obj  : in out SFR.Finalizable);
   --  Call Finalize on Obj and remove its final list

   ---------------------
   -- Deep Procedures --
   ---------------------

   procedure Deep_Tag_Attach
     (L : in out SFR.Finalizable_Ptr;
      A : System.Address;
      B : Short_Short_Integer);
   --  Generic attachment for tagged objects with controlled components.
   --  A is the address of the object, L the finalization list when it needs
   --  to be attached and B the attachment level (see Attach_To_Final_List).

   -----------------------------
   -- Record Controller Types --
   -----------------------------

   --  Definition of the types of the controller component that is included
   --  in records containing controlled components. This controller is
   --  attached to the finalization chain of the upper-level and carries
   --  the pointer of the finalization chain for the lower level.

   type Limited_Record_Controller is new SFR.Root_Controlled with record
      F : SFR.Finalizable_Ptr;
   end record;

   overriding procedure Initialize (Object : in out Limited_Record_Controller);
   --  Does nothing currently

   overriding procedure Finalize (Object : in out Limited_Record_Controller);
   --  Finalize the controlled components of the enclosing record by following
   --  the list starting at Object.F.

   type Record_Controller is
      new Limited_Record_Controller with record
         My_Address : System.Address;
      end record;

   overriding procedure Initialize (Object : in out Record_Controller);
   --  Initialize the field My_Address to the Object'Address

   overriding procedure Adjust (Object : in out Record_Controller);
   --  Adjust the components and their finalization pointers by subtracting by
   --  the offset of the target and the source addresses of the assignment.

   --  Inherit Finalize from Limited_Record_Controller

   procedure Detach_From_Final_List (Obj : in out SFR.Finalizable);
   --  Remove the specified object from its Final list, which must be a doubly
   --  linked list.

end System.Finalization_Implementation;